When downloading from YouTube, the first decision you make is format: MP4 or MP3. It seems simple — video or audio — but the right choice depends on what you plan to do with the file, which devices you will use, and how much storage you have. This guide gives you everything you need to make the right call every time.
The One-Line Answer
Download MP4 if you want to watch the video. Download MP3 if you only need the audio. The rest of this guide explains why, what the trade-offs are, and when it gets more complicated.
What Is MP4?
MP4 (MPEG-4 Part 14) is a digital multimedia container format. It stores video, audio, subtitles, and metadata together in one file. When you download a YouTube video as MP4, you get the complete visual and audio experience — exactly what you would see on YouTube, saved to your device.
MP4 is the most widely supported video format in the world. It plays natively on:
- Windows (built-in Films & TV app)
- Mac (QuickTime)
- iPhone and iPad (Files app, Photos)
- Android (any default video player)
- Smart TVs, PlayStation, Xbox
- VLC and every major media player
You will almost never encounter a device that cannot play an MP4 file. This universality is why MP4 became the dominant video format for online video.
What Is MP3?
MP3 (MPEG-1 Audio Layer III) is an audio-only format. When EasyYTDown creates an MP3 from a YouTube video, it extracts just the audio track and discards the video. The result is a smaller file that contains only sound — no picture, no video stream.
MP3 plays on:
- Every phone, tablet, and computer ever made in the last 25 years
- Car stereos (via USB, Bluetooth, or CD-R)
- iPods, MP3 players, smartwatches
- Smart speakers (Amazon Echo, Google Home via Bluetooth)
- Podcast apps (Pocket Casts, Overcast, Spotify)
MP3 is arguably the most universally compatible audio format ever created. If a device can play audio, it almost certainly supports MP3.
MP4 vs MP3 — Head-to-Head Comparison
File Size Difference — Why It Matters
The most practical difference between MP4 and MP3 is file size. A 10-minute YouTube video:
- As MP4 at 720p: approximately 150–300 MB
- As MP4 at 1080p: approximately 300–600 MB
- As MP3 at 128kbps: approximately 9–12 MB
MP3 is roughly 20–50x smaller than MP4. This matters when you have limited storage on your phone or want to download many items. If you are saving a 2-hour lecture for the train, as MP4 it might be 2–4 GB. As MP3, it is 100–150 MB — about the size of a few photos.
When to Download as MP4
- You need to see what is happening: Tutorials, demonstrations, documentaries, vlogs, sports — anything where the visuals matter
- You are watching on a TV or large screen: MP4 at 1080p looks great; there is no video version of MP3
- The visual information is essential: Cooking videos, how-to guides, nature documentaries
- You want to keep the original quality: If you might watch it again years later, MP4 preserves everything the creator intended
- You need subtitles or closed captions: MP4 can embed subtitles; MP3 cannot
When to Download as MP3
- Music and songs: You only need to hear the music, not watch the music video
- Podcasts: Many podcasters post to YouTube — MP3 lets you add them to your podcast app
- Lectures and educational talks: If you can follow along without watching the screen (most lectures), MP3 saves huge amounts of storage
- Motivational speeches and TED Talks: Pure audio is usually enough for spoken content
- Language learning audio: Repeat playback of pronunciation examples, dialogues, and exercises
- Background listening: Content you play while cooking, exercising, or commuting
- Storage-limited devices: If your phone has 2 GB free and you want 10 hours of content, MP3 is the only practical choice
Audio Quality in MP4 vs MP3
This surprises many people: the audio inside an MP4 file and an MP3 file from the same source can sound identical. YouTube's audio stream is typically AAC at 128–192 kbps. When EasyYTDown creates an MP3, it converts this to MP3 at a matching bitrate. The conversion process is extremely fast with FFmpeg and the audio quality loss (if any) is imperceptible to human ears.
If you care deeply about audio fidelity — you have high-end headphones and listen critically — you might prefer to download as MP4 and extract the audio with a lossless tool. But for 99% of listeners, the MP3 sounds the same as watching on YouTube.
Can You Extract Audio from an MP4 File Later?
Yes. If you downloaded MP4 and later want just the audio, you can extract it using free tools:
- VLC Media Player: File → Convert / Stream → select audio-only MP3 output
- FFmpeg (command line):
ffmpeg -i video.mp4 -q:a 0 -map a audio.mp3 - Audacity: Open the MP4 file and export as MP3
- Online converters: Various browser-based tools convert MP4 to MP3 without software
The reverse — adding video to an MP3 — is not practically useful, so if you think you might want the video later, download MP4 to begin with.
What About Other Formats — WebM, MKV, AVI?
YouTube actually streams video in WebM format (VP9/AV1 video codec, Opus audio) internally. EasyYTDown converts this to MP4 because MP4 has broader compatibility. You will occasionally see other formats mentioned:
- WebM: Good quality, smaller than MP4, but poor compatibility on Apple devices and older players
- MKV: Excellent for high-quality video, but not natively supported on most phones and smart TVs without VLC
- AVI: Old format, large files, not recommended for modern use
- AAC: Better audio quality than MP3 at the same bitrate — but MP3 is more universally compatible
For most users, MP4 for video and MP3 for audio covers every use case without compatibility headaches.
Frequently Asked Questions
Can I play MP3 files downloaded from YouTube in Spotify or Apple Music?
Spotify does not support local MP3 files on mobile (only desktop with a workaround). Apple Music does — you can add MP3 files to your local library and sync them to your iPhone. VLC and similar apps play MP3s on any platform without restrictions.
I downloaded MP4 but I only hear audio — is it broken?
No. An MP4 file plays both video and audio. If you only hear audio, your media player may not support the video codec. Install VLC Media Player (free) and try again — it plays all MP4 variants.
Which format downloads faster — MP4 or MP3?
MP3 downloads are generally faster because the file is much smaller. An MP3 from a 10-minute video might be 10 MB; the MP4 version at 720p is 150–200 MB. Processing time on EasyYTDown's server also takes slightly longer for video.
Which is better for WhatsApp sharing — MP4 or MP3?
WhatsApp supports both MP4 video files and MP3 audio files. For video sharing, use MP4. For audio messages or music sharing, MP3 is smaller and faster to send. WhatsApp has a 100 MB file size limit for media sharing — keep this in mind for long videos.
Is MP3 free to use on EasyYTDown?
MP3 extraction is a Pro feature on EasyYTDown ($4.99/month). MP4 video downloads in 360p, 480p, and 720p are available free (5 downloads/day, no sign-up).
Summary — Choose Based on Your Use Case
The format decision is straightforward once you know what you need:
- Need to see it → MP4
- Only need to hear it → MP3
- Watching on a big screen → MP4 at 1080p
- Limited storage → MP3
- Adding to a podcast app → MP3
- Sharing a funny clip → MP4